Speed HEVC encoding on iMacPro

Not sure the MacBook Pro has hardware acceleration but the iMac Pro definitely does.

I have been experimenting with HEVC or x265 encoding (same thing) and it is really processor intensive and time consuming on older hardware, it makes my older Macs run really hot. It also may not result in a better render if you are converting from an x264 or divx video, it can produce quite severe artefacts. But if you are coming from a good quality high resolution, high frame rate video it gives smoother and more vivid colors, particularly if you have flat areas of color as in animations.

Take a small sample of the video and experiment in Handbrake, varying the settings and adding the settings into the rendered files name to discover which works best for what material.

For many files there is little reason to use HEVC for the small size improvement. The files will not run in older versions of Quiktime Player, you will have to open them in VLC which is a less smoother UI.

Peter

Depends what you want from your video.

Most would benefit more from a plot and better writing than cgi and higher resolution.

But if you can’t have ideas or good writing I suppose higher resolution will have to do.

Peter

This is strange, because on may iMac Pro it's slow as molasses and in compressor the 8-bit option is shown as not compatible.

I don't think the 2013 Mac Pro is capable of doing hardware-based HEVC encoding. So it's doing that all in software (at least running on the CPU and possibly the GPU).

Newer Macs (I believe starting with the 2017 iMac) and newer iOS devices would have hardware acceleration.

Thus, it's probably not readily easy to figure out how fast the various iMac Pro setups would be.

Maybe look at various video forums both here and on other web sites to see if anyone has encoding timings on a 2017 iMac. That will at least give you a more known baseline. And then, depending upon which iMac Pro you're looking at, should be able to estimate what that will be capable of.

Finally, I wouldn't be surprised if the iPhone is using certain profiles of HEVC to balance power consumption, encode/decode speed, etc. Compressor's settings that you've used could be a much more aggressive (and compute-heavy) scenario. So not only are you doing software-based encoding, but you could also be doing a more intensive encode too.

Finally able to conduct some tests today with a 3 minute, 18-second H.264 clip (1080p, 8-bit 4:2:0, 29.97 fps).

Old Mac (2012 12-Core Mac Pro, 32 GB RAM, Radeon HD 5870 1 GB). Source drive read speed of 100 MBps. Destination drive (separate) a write speed of around 120 MBps. Conversion would have taken around 45 minutes (I stopped it at the 6-minute mark and it had around 40 minutes left to go).

New Mac (2017 10-Core iMac Pro. 64 GB RAM, Radeon Pro Vega 56 8 GB). Source RAID read speed of 600 MBps. Destination RAID (separate unit) a write speed of 400 MBps. Conversion took around 56 seconds.

I just used Apple's 'QuickTime Player' to do an export to 1080p while checking the HEVC checkbox. Both systems also running the same macOS (10.13.2).

Thus, you'll really want a Mac with hardware acceleration for HEVC. And while my new storage is drastically faster in the new Mac, this test wasn't I/O bound. But, I wanted to reveal all the details.

The 2017 MacBook Pros contain 7th-gen Intel Core processors. Thus, I belive they would be able to support hardware accelerated HEVC.